Emily LakdawallaAug 27, 2016

Juno's first Jupiter close approach successful; best JunoCam images yet to come

NASA announced this afternoon that Juno passed through its first perijove since entering orbit successfully, with science instruments operating all the way. This is a huge relief, given all the unknowns about the effects of Jupiter's nasty radiation environment on its brand-new orbiter.

NASA's Juno mission successfully executed its first of 36 orbital flybys of Jupiter today. The time of closest approach with the gas-giant world was 6:44 a.m. PDT (9:44 a.m. EDT, 13:44 UTC) when Juno passed about 2,600 miles (4,200 kilometers) above Jupiter's swirling clouds. At the time, Juno was traveling at 130,000 mph (208,000 kilometers per hour) with respect to the planet. This flyby was the closest Juno will get to Jupiter during its prime mission.

"Early post-flyby telemetry indicates that everything worked as planned and Juno is firing on all cylinders," said Rick Nybakken, Juno project manager....

While results from the spacecraft's suite of instruments will be released down the road, a handful of images from Juno's visible light imager -- JunoCam -- are expected to be released the next couple of weeks. Those images will include the highest-resolution views of the Jovian atmosphere and the first glimpse of Jupiter's north and south poles.

They released one processed image from JunoCam, taken on approach to perijove, from a distance of 703,000 kilometers. I checked JPL's Horizons web tool and determined that the photo was captured two hours before closest approach, roughly an hour before the spacecraft would have passed over the north pole. So it's just a taste of the awesome imaging to come -- there should be much better stuff in the future. For now, though, just pause and appreciate what an unusual view this is -- a crescent Jupiter, tipping over to show its north pole to us.

Juno approaches its first orbital perijove
Juno approaches its first orbital perijove Juno captured this photo of Jupiter about two hours before Perijove 1, from a distance of 703,000 kilometers, at 04:45 UTC on August 27, 2016. The spacecraft had yet to travel over Jupiter's north pole.Image: NASA / JPL / SwRI / MSSS / Ted Stryk

I don't know what other images have been planned, because the mission has inexplicably chosen not to share information with the public about those plans. This is really weird, because Cassini and New Horizons were both very open about their plans for imaging with their science cameras. Juno's JunoCam is an instrument intended specifically for public outreach, and yet they're keeping information about it close to the vest. Apart from the types of imaging mentioned in the press release, there has been discussion of attempting 3D imaging of clouds by taking images closely spaced in time as the spacecraft passes from north to south. There was also an opportunity to image Ganymede yesterday. We'll have to wait and see!

Late last week the Juno team did release more frames from the "Marble Movie," teeny snapshots of Jupiter taken through August 22. I've posted all that data to my JunoCam data page. Gerald Eichstaedt made thumbnails of all the images, and I assembled them into this movie montage. Have fun hunting for moon and shadow transits! Data should now be on Earth for everything that JunoCam imaged between these frames and the photo shown above; I'll certainly let y'all know when it's publicly available.

JunoCam's "Marble Movie" frames, July 10-August 21, 2016
JunoCam's "Marble Movie" frames, July 10-August 21, 2016 During its first long orbit around Jupiter, JunoCam took color photos of the planet every 15 to 30 minutes, seeing it spin, watching the red spot, and observing moons and moon shadows crossing the disk. Access the raw data for all these images here.Image: NASA / JPL / SwRI / MSSS / Gerald Eichstaedt / Emily Lakdawalla





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